Abstract:

The present invention is a telescopic composite cylinder that functions as
a hydraulic hoist incorporating multiple cylinders formed of composite
materials. The walls of the multiple cylinders may be formed of pultruded
composite material, or a combination of composite materials. The
cylinders of the hydraulic hoist may incorporate a plurality of piston
and sleeve assemblies that are mounted so as to invoke a telescopic
relationship between the multiple cylinders. The materials that the
cylinders are formed of may create walls having a smooth surface that can
eliminate problems facing hoists formed of other materials, for example,
such as a honing process, fluid leakage and seal wearing problems. The
hoist may be run on diesel fuel drawn from the tank of a vehicle.
Additionally, the present invention may be releseably attached to a
surface by way of a saddle mounting system.

Claims:

1. A composite material telescopic multi-cylinder hydraulic hoist,
comprising:(a) an outer stage cylinder having one end sealed by a base
member and an open end, formed of a composite material;(b) at least one
additional cylinder disposed within the open end of the said outer stage
cylinder such that there is an overlap between said cylinder stages, said
at least one additional cylinder stage being formed of a composite
material;(c) a hydraulic fluid port in communication with an interior of
the cylinder stages; and(d) at least one seal mounted between cylinder
stages, whereby forcing hydraulic fluid into said hydraulic fluid port
causes said at least one additional cylinder stage to extend relative to
said outer cylinder stage;whereby the cylinder stages have a modulus of
elasticity which allows the cylinder stages to expand under the force of
a momentary pressure spike, and upon release of the pressure spike, to
retract to their original configuration.

2. The composite material telescopic multi-cylinder hydraulic hoist of
claim 1, wherein the outer stage cylinder and the at least one additional
cylinder incorporate a plurality of piston and sleeve assemblies.

3. The composite material telescopic multi-cylinder hydraulic hoist of
claim 1, wherein a telescopic relationship is invoked between the outer
stage cylinder and the at least one additional cylinder and the outer
stage cylinder and the at least one additional cylinder form a six-stage
composite cylinder.

6. The composite material telescopic multi-cylinder hydraulic hoist of
claim 1, wherein the composite material is smooth on its surface whereby
minimal friction occurs between the outer stage cylinder and the at least
one additional cylinder upon extension or collapse of said outer stage
cylinder and the at least one additional cylinder, and whereby the
requisite pressure to extend the composite material telescopic
multi-cylinder hydraulic hoist is minimized.

7. The composite material telescopic multi-cylinder hydraulic hoist of
claim 6, wherein the smooth composite material averts one or more of the
following: a honing process; hydraulic fluid leakage; or wearing of the
at least one seal.

10. The composite material telescopic multi-cylinder hydraulic hoist of
claim 1, wherein the outer stage cylinder and the at least one additional
cylinder extend or collapse in a manner of double-acting cylinders.

12. A telescopic multi-cylinder hydraulic hoist mountable upon a vehicle
having a fuel tank, comprising:(a) an outer stage cylinder having one end
sealed by a base member and an open end, formed of a composite
material;(b) at least one additional cylinder disposed within the open
end of the said outer stage cylinder such that there is an overlap
between said cylinder stages, said at least one additional cylinder stage
being formed of a composite material;(c) a hydraulic fluid port in
communication with an interior of the cylinder stages; and(d) at least
one seal mounted between cylinder stages, whereby forcing hydraulic fluid
into said hydraulic fluid port causes said at least one additional
cylinder stage to extend relative to said outer cylinder stage, the
hydraulic fluid being drawn from the fuel tank of the vehicle;whereby the
cylinder stages have a modulus of elasticity which allows the cylinder
stages to expand under the force of a momentary pressure spike, and upon
release of the pressure spike, to retract to their original
configuration.

13. The telescopic multi-cylinder hydraulic hoist mountable upon a vehicle
of claim 12, wherein the hydraulic fluid is drawn from the fuel tank of
the vehicle by a hydrostatic pump and the drawing of hydraulic fluid
decreases the overall weight of the hoist when said hoist is mounted upon
the vehicle.

14. The telescopic multi-cylinder hydraulic hoist mountable upon a vehicle
of claim 12, wherein the hydraulic fluid is diesel fuel.

15. The telescopic multi-cylinder hydraulic hoist mountable upon a vehicle
of claim 12, wherein the hoist is formed of a composite material.

16. A telescopic multi-cylinder hydraulic hoist releaseably mounted on a
vehicle, comprising:(a) an outer stage cylinder having one end sealed by
a base member and an open end, formed of a composite material;(b) at
least one additional cylinder disposed within the open end of the said
outer stage cylinder such that there is an overlap between said cylinder
stages, said at least one additional cylinder stage being formed of a
composite material;(c) a hydraulic fluid port in communication with an
interior of the cylinder stages;(d) at least one seal mounted between
cylinder stages, whereby forcing hydraulic fluid into said hydraulic
fluid port causes said at least one additional cylinder stage to extend
relative to said outer cylinder stage, the hydraulic fluid being drawn
from the fuel tank of the vehicle; and(e) a saddle mounting system to
releaseably attach the telescopic multi-cylinder hydraulic hoist to the
vehicle;whereby the cylinder stages have a modulus of elasticity which
allows the cylinder stages to expand under the force of a momentary
pressure spike, and upon release of the pressure spike, to retract to
their original configuration; andwhereby the saddle mounting system
functions so that if the vehicle tips-over the saddle mounting system
breaks away from the composite cylinder and the composite cylinder
remains unstressed.

17. The telescopic multi-cylinder hydraulic hoist releasably mountable
upon a vehicle of claim 16, wherein the hoist is formed of a composite
material.

18. The telescopic multi-cylinder hydraulic hoist releasably mountable
upon a vehicle of claim 17, wherein the composite material is at least
one of the following:resistant to fatigue; orof high tensile and yield
strengths.

19. The telescopic multi-cylinder hydraulic hoist releasably mountable
upon a vehicle of claim 16, wherein the saddle mounting system attaches
to the outer stage cylinder.

20. The telescopic multi-cylinder hydraulic hoist releasably mountable
upon a vehicle of claim 16, wherein the saddle mounting system
comprises:a saddle lower mount having a saddle shape that points away
from the lower end of the outer stage cylinder when it is releasably
attached to the hoist; anda lower mount pivot bar positioned within the
saddle shape of the saddle lower mount, said lower mount pivot bar being
releasably fixed within the saddle shape by one or more saddle attachment
means at a first end and attached to a surface of the vehicle at a second
end by a vehicle attachment means.

Description:

[0002]This invention relates in general to the field of hydraulic hoists
and in particular to hydraulic hoists formed of composite materials.

BACKGROUND OF THE INVENTION

[0003]Heavy duty telescoping hydraulic hoists, such as are commonly used
in dump trucks and the like, are typically composed of steel. Steel is a
strong, relatively rigid metal which, when formed to a suitable wall
thickness, provides the necessary support for the hoist and its load, and
operates effectively under the extremely high hydraulic pressures to
which such devices are subjected.

[0004]Telescopic hydraulic hoists are increasing in popularity in the
haulage trucking industry. Competitors entering the market include Custom
Hoist, Hyco 3000, Edbro, and Hyva Group. Custom Hoist, Hyco 3000 and
Edbro all produce steel hoists. The Hyva Group produces a telescopic
hydraulic hoist that is approximately 60% lighter than known prior art
hoists.

[0005]U.S. Pat. No. 6,899,014 discloses a hydraulic hoist having tube
stage walls formed from a heat treated aluminum alloy from one of the
series 2000, 6000 or 7000 aluminum alloys. Such alloys retain "memory"
properties. Under the force of a pressure spike the alloys undergo a
momentary elastic deformation which acts as a shock absorber. The tube
wall is expanded to absorb the peak stresses and resist buckling. The
hoist disclosed in this patent is lighter than the steel hoists of the
prior art, and is also more resistant to corrosion.

SUMMARY OF THE INVENTION

[0006]In one aspect, the present disclosure relates to a composite
material telescopic multi-cylinder hydraulic hoist, comprising: an outer
stage cylinder having one end sealed by a base member and an open end,
formed of a composite material; at least one additional cylinder disposed
within the open end of the said outer stage cylinder such that there is
an overlap between said cylinder stages, said at least one additional
cylinder stage being formed of a composite material; a hydraulic fluid
port in communication with an interior of the cylinder stages; and at
least one seal mounted between cylinder stages, whereby forcing hydraulic
fluid into said hydraulic fluid port causes said at least one additional
cylinder stage to extend relative to said outer cylinder stage; whereby
the cylinder stages have a modulus of elasticity which allows the
cylinder stages to expand under the force of a momentary pressure spike,
and upon release of the pressure spike, to retract to their original
configuration.

[0007]In another aspect, the present disclosure relates to a telescopic
multi-cylinder hydraulic hoist mountable upon a vehicle having a fuel
tank, comprising: an outer stage cylinder having one end sealed by a base
member and an open end, formed of a composite material; at least one
additional cylinder disposed within the open end of the said outer stage
cylinder such that there is an overlap between said cylinder stages, said
at least one additional cylinder stage being formed of a composite
material; a hydraulic fluid port in communication with an interior of the
cylinder stages; and at least one seal mounted between cylinder stages,
whereby forcing hydraulic fluid into said hydraulic fluid port causes
said at least one additional cylinder stage to extend relative to said
outer cylinder stage, the hydraulic fluid being drawn from the fuel tank
of the vehicle; whereby the cylinder stages have a modulus of elasticity
which allows the cylinder stages to expand under the force of a momentary
pressure spike, and upon release of the pressure spike, to retract to
their original configuration.

[0008]In yet another aspect, the present disclosure relates to a
telescopic multi-cylinder hydraulic hoist releaseably mounted on a
vehicle, comprising: an outer stage cylinder having one end sealed by a
base member and an open end, formed of a composite material; at least one
additional cylinder disposed within the open end of the said outer stage
cylinder such that there is an overlap between said cylinder stages, said
at least one additional cylinder stage being formed of a composite
material; a hydraulic fluid port in communication with an interior of the
cylinder stages; at least one seal mounted between cylinder stages,
whereby forcing hydraulic fluid into said hydraulic fluid port causes
said at least one additional cylinder stage to extend relative to said
outer cylinder stage, the hydraulic fluid being drawn from the fuel tank
of the vehicle; and a saddle mounting system to releaseably attach the
telescopic multi-cylinder hydraulic hoist to the vehicle; whereby the
cylinder stages have a modulus of elasticity which allows the cylinder
stages to expand under the force of a momentary pressure spike, and upon
release of the pressure spike, to retract to their original
configuration; and whereby the saddle mounting system functions so that
if the vehicle tips-over the saddle mounting system breaks away from the
composite cylinder and the composite cylinder remains unstressed.

[0009]In this respect, before explaining at least one embodiment of the
invention in detail, it is to be understood that the invention is not
limited in its application to the details of construction and to the
arrangements of the components set forth in the following description or
illustrated in the drawings. The invention is capable of other
embodiments and of being practiced and carried out in various ways. Also,
it is to be understood that the phraseology and terminology employed
herein are for the purpose of description and should not be regarded as
limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]The invention will be better understood and objects of the invention
will become apparent when consideration is given to the following
detailed description thereof. Such description makes reference to the
annexed drawings wherein:

[0011]FIG. 1 is a side-view of the present invention.

[0012]FIG. 2 is a partial sectional-view of the present invention.

[0013]FIG. 3 is a perspective-view of the saddle mounting system of the
present invention.

[0014]In the drawings, embodiments of the invention are illustrated by way
of example. It is to be expressly understood that the description and
drawings are only for the purpose of illustration and as an aid to
understanding, and are not intended as a definition of the limits of the
invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0015]The present invention is a telescopic composite cylinder that
functions as a hydraulic hoist incorporating multiple cylinders formed of
composite materials. The walls of the multiple cylinders may be formed of
pultruded composite material, or a combination of composite materials.
The cylinders of the hydraulic hoist may incorporate a plurality of
piston and sleeve assemblies that are mounted so as to invoke a
telescopic relationship between the multiple cylinders. The materials
that the cylinders are formed of may create walls having a smooth surface
that can eliminate problems facing hoists formed of other materials, for
example, such as a honing process, fluid leakage and seal wearing
problems. The hoist may be run on diesel fuel drawn from the tank of a
vehicle, such as, for example, the vehicle that the hoist is transported
upon. Running the hoist on diesel fuel may offer multiple means of
decreasing the overall weight of the invention, such as, for example,
decreasing the weight of the hoist load by eliminating the need for a
second tank. Additionally, the present invention may be releseably
attached to a surface by way of a saddle mounting system. The saddle
mounting system functions so that should the composite cylinder be
releaseably attached to a trailer that tips-over the bolts of the saddle
mounting system may break away from the composite cylinder before the
composite cylinder can be stressed. In this manner damage to the
composite cylinder, and any environment damage possibly caused by leakage
of hydraulic fluid, may be averted.

[0016]The present invention is constructed and operates in a manner
similar to that shown and described in the inventor's U.S. Pat. No.
6,899,014 issued to the inventor May 31, 2005, which is incorporated
herein by reference. A skilled reader will recognize that the present
invention may be operable to undertake any task that a heavy duty
telescoping hydraulic hoist may achieve, such as, for example use in a
dump truck or any other high load-bearing application. A skilled reader
will further recognize that the present invention is not restricted to
any particular embodiment illustrated in the drawings.

[0017]In general, the present invention is a composite cylinder formed of
multiple cylinders that may operate in a telescopic manner. The multiple
cylinders may nest inside one another when the composite cylinder is
collapsed. The multiple cylinders may be positioned sequentially when the
composite cylinder is extended. The multiple cylinders that collectively
comprise the composite cylinder, may each be a stage, a moving stage, or
a tube. A skilled reader will recognize the various terms that may be
utilized to describe the cylinders of embodiments of the present
invention. The cylinders may be shaped to have a diameter that decreases
from one end to another, moreover, the diameter of each cylinder may
decrease sequentially in relation to the preceding cylinder. Pressure
exerted within the cylinders, such as by hydraulic fluid, may cause the
composite cylinder to alter between a collapsed and an extended state.
Additionally the composite cylinder may be utilized to extend to
positions that are less than a fully extended state.

[0018]The present invention represents benefits over the prior art. For
example, hoists formed of steel are very heavy. This heaviness can reduce
the efficiency of vehicles such as dump trucks that have to carry the
hoist when transporting a load. Moreover, steel corrodes at a fairly high
rate, which reduces the life of the rings and seals that are used to
contain the hydraulic fluid and to ensure that the stages move freely
relative to one another, and reduces the durability of the hoist
components in general. It is therefore advantageous to construct a
telescoping hydraulic hoist from a non-corrosive material which is
lighter than steel, such as the hydraulic hoist formed of composite
material of the present invention. This can considerably reduce the
weight of the hoist and significantly extend the useful life of many of
its components.

[0019]The present invention also represents a benefit over hydraulic
hoists formed of pure aluminum. It has been found that pure aluminum is
too soft and weak to support the type of load that such hoists are
designed to lift. The hydraulic hoist formed of composite material of the
present invention is stronger than hoists formed of aluminum.

[0020]The present invention also offers benefits over hoists formed of
aluminum alloys. Such aluminum alloys may include alloys composed of at
least 75% aluminum and containing one or more other metallic elements
such as copper, manganese, magnesium, silicon, zinc, and/or lithium, and
can be considerably stronger than pure aluminum. The additional metallic
elements are known to substantially improve many mechanical
characteristics of the alloy over pure aluminum, including its strength,
particularly in the case of heat treatable aluminum alloys which can be
processed to have strength comparable to that of steel. However, the
modulus of elasticity of aluminum is typically around one-third of the
modulus of elasticity of steel. It is commonly believed that even heat
treated aluminum alloys would deform under stresses which would not
affect steel, causing the hoist to buckle under peak stresses which can
be encountered during normal operation, and especially if the hoist
malfunctions or if it is operated in an abusive or careless fashion.

[0021]In the heavy duty hydraulic hoist industry buckling is a major
concern, and the low modulus of elasticity of aluminum alloys has
resulted in the universal perception that such alloys are unsuitable for
use in heavy-duty hydraulic cylinders. This perception includes low
buckling point, and an inability to withstand the severe shocks, stresses
and spikes in pressure that such hydraulic cylinders are subject to
especially when used for dump trucks and other similar high stress
applications. It is accordingly conventionally believed that such
materials are unsuitable for use in heavy duty hydraulic hoist
applications. As a result there are no heavy duty aluminum hydraulic
cylinders available in the market, although aluminum is in common use for
light duty applications.

[0022]The present invention offers a benefit over prior art hoists formed
of aluminum alloys in that it offers a lighter hoist that has sufficient
strength to undertake heavy duty applications. In certain industries
(such as the trucking industry), any significant reduction in weight is
extremely valuable because it increases available payload, and reduces
fuel consumption and wear and tear on the vehicle. Thus the weight saving
of the present invention over prior art steel hoists that are currently
the standard can be substantial, potentially running into hundreds of
tons. In addition, the present invention may offer significant
environmental benefits because it may be feasible to employ a water-based
hydraulic medium that is environmentally friendly and less expensive than
oil.

[0023]In one embodiment of the present invention, as shown in FIG. 1, the
hoist 10 may be formed of two or more cylinders 16 and 17. Such cylinders
may be formed in a manner whereby the cylinders are of graduating sizes,
so that one cylinder may be fit within another cylinder. For example, as
shown in FIG. 1, an inner cylinder 17 may fit within an outer cylinder
16. In other embodiments of the present invention one or more additional
cylinders, being progressively smaller than cylinder 17, may be fit
within cylinder 17.

[0024]In one embodiment of the present invention, as shown in FIG. 2,
multiple cylinders may nest within each other and fit together in a
slideable manner whereby they are extendable in a telescopic manner. The
smallest cylinder may be the innermost cylinder and the largest cylinder
may be the outermost cylinder 16. Other than size each cylinder, other
than the outermost cylinder, may be similar to the other cylinders in
that each may have a limiting band 22, an upper bearing 46 and a lower
bearing 26 with a seal 24. Cylinders may further incorporate a wiper 42
and a gland nut 40 applied to hold a cylinder in position when said
cylinder is not extended. An inner cylinder may be slid so as to protrude
beyond the limits of an outer cylinder, may be slid so as to fit wholly
within the outer cylinder, or may be slid to any intermediate position
that causes a portion of the inner cylinder to protrude from an outer
cylinder.

[0025]As shown in FIG. 2, a limiting band 22 may be positioned at the end
of the cylinder, being the end from which an additional cylinder may
protrude. A limiting band may have a seal 24 positioned thereupon that
seals the space between a cylinder 16 and the other cylinder 17 that
protrudes therefrom. This seal may keep hydraulic fluids, utilized to
cause the cylinder hoist to function, contained in the space between the
cylinders. The seal therefore keeps the hydraulic fluid from leeching
into the environment where it may cause contamination.

[0026]As shown in FIG. 1, a retaining band 20 may be positioned at the end
of the last of the nesting cylinders that does not have another cylinder
fit therewithin. The retaining band may be coupled with an upper
retaining band 18 and a lower bearing 26.

[0027]In one embodiment of the present invention, a mount may be attached
to the innermost cylinder, being the smallest cylinder. The mount 32 may
be utilized to attach the hoist 10 to a surface, such as a surface of a
vehicle, for example a truckbed. The mount 32 may include a bearing 28,
to permit the hoist 10 to be rotatable while attached to the surface. A
valve 30 may also be attached to the mount whereby air, hydraulic fluid
or any other substance trapped within the hoist or the mount may be
released. A skilled reader will recognize that a mount may be attached to
the composite cylinder in many ways and may be attached to cylinders
other than the innermost cylinder, such as, for example the outermost
cylinder.

[0028]The present invention may be formed of composite material. Such a
material may diminish fatigue, as is experienced by some metals.
Composite material may also be resistant to rust and pitting. A skilled
reader will recognize that a variety of composite materials that may be
utilized to form the present invention. For example, one such composite
material that may be utilized is carbon fiber. Carbon fiber is generally
lighter than aluminum and stronger than steel on a pound for pound basis.
Additionally, carbon fiber may be molded into complex shapes and sizes.
Carbon fiber may also be "laid-up" with more or less material wherever
necessary. Utilizing carbon fiber to form the cylinders and other pieces
of the present invention may permit the creation of pieces of the hoist
that include particular specifications, for example, such as oversized
diameters, unique shapes and exaggerated tapers.

[0029]The present invention may be formed of a variety of composite
materials, or a collection thereof, including: polymeric material;
synthetic resins, such as polyethylene, polypropylene, polybutene;
fibers; cords; molded cylinders; protrusion cylinders; stiff organic or
inorganic fibers, such as bamboo or silk; and carbon fibers such as
Kevlar, an aromatic polyamide. A skilled reader will recognize that other
materials may also be utilized to form the present invention.

[0030]Any cylinder or other piece of the present invention formed from
composite material may be able to withstand high temperatures and
pressures. In particular, pressures may be withstood through elasticity
of the material whereby it may absorb pressure and pressure will not
cause the material to lose its shape, as it retains that shape as
"memory" and will return to the original shape upon the cessation of
pressure. The modulus of elasticity of a material is a measure of a
stress applied to the material divided by strain, within the elastic
range of the material. The strain is the ratio of the amount of
deformation caused by the stress to the initial length of the material.
Therefore, a material which stretches more under a given stress has a
lower modulus of elasticity. The present invention being formed of
composite material may not require an increase in the thickness of the
tube stage walls over the thickness of a counterpart formed of another
material, such as steel or aluminum, proportionate to the difference in
the modulus of elasticity. The wall thickness may be governed by the
theoretical value of deflection. For example, wall thickness may be
determined to achieve an approximate maximum deflection of 0.500 inch
under ten metric tons load applied in the center of the tube of the
composite cylinder. A skilled reader will recognize that other
deflections and loads may be applied to determine the wall thicknesses
applied in the present invention. The present invention being formed of
composite material may additionally project high tensile and yield
strengths.

[0031]The composite material forming the cylinders may be pultruded or
molded. Pultruded cylinders in particular may have smooth surfaces.
Pultrusion is a continuous process of manufacturing of composite
materials involving at least the step of reinforced fibers being pulled
through a resin. Smooth surfaces enhance the extension and collapsing of
the cylinders by decreasing the incident of friction between the surfaces
of the cylinders as they move against each other. This may have the
effect of decreasing the pressure required to extend the cylinders.

[0032]Cylinders formed from composite material may be resistant to
pitting. When sand or other matter comes in contact with some metals,
such as, for example aluminum or steel, the abrasion created by the
contact between the metal and the matter can cause pitting of the metal.
To protect metals prone to pitting the metal may be chrome plated,
however this can be an expensive undertaking. Composite material offers a
benefit over other materials in that it is resistant to pitting and
therefore retains a smooth surface in the face of contact with abrasive
materials. The smooth surface of the composite material may aid the
smooth operation of the composite cylinder particularly as it operates in
a telescopic manner and its cylinders extend and collapse in relation to
one another.

[0033]In one embodiment of the present invention, the lower mount of the
cylinders may consist of a saddle mounting system. Such a mounting system
offers benefits over known prior art mounting means.

[0034]Prior art mounting means for cylinders generally involve a pinned
hinge system, similar to the hinge of a door. In a pinned hinge system, a
lower mount is attached to a trailer bed. A cylinder is positioned over
the lower mount. A mount pin passes through mount holes of the lower
mount, as well as through a mounting hole, or pipe formed, at the base of
a steel cylinder. The effect of the pinned hinge system is that the
cylinder is affixed to the trailer unit in a manner whereby, in the
situation that the trailer tips-over, as the trailer bed falls sideways,
it will put stress on the lower mount. This stress may cause the cylinder
to fail and result in the release of the toxic hydraulic fluids into the
environment.

[0035]The saddle mounting system of the present invention, as shown in
FIG. 3, may incorporate a saddle lower mount 66 that is shaped like a
saddle, having an inverted-U or inverted-cup shape. The composite
cylinder may be positioned to connect to the outermost cylinder in a
manner whereby the saddle shaped portion of the saddle lower mount points
away from the lower end of the outermost cylinder. A lower mount pivot
bar 68 may be positioned within the saddle shaped portion of the saddle
lower mount. The lower mount pivot bar may be releaseably fixed within
the saddle portion by one or more retaining bolts 62. The one or more
retaining bolts may be fitted through holes in the lower portion of the
saddle portion, so that the retaining bolts are positioned below the
lower mount pivot bar. The pivot bar may be clamped to a surface, such
as, for example a trailer bed, by a variety of clamping means. A skilled
reader will recognize that many clamping means as well as other
attachment means may be applied to releaseably attach the composite
cylinder to a surface. Should the composite cylinder be releaseably
attached to a trailer, in the case that the trailer tips-over the bolts
may break away from the composite cylinder before the composite cylinder
can be stressed. In this manner damage to the composite cylinder may be
averted. Additionally, hydraulic fluid may be prevented from leaking into
the environment.

[0036]One embodiment of the present invention may be a six-stage composite
cylinder. Such a cylinder may incorporate a closed volume of
approximately 15 gallons and an open volume of approximately 73 gallons.
The closed length of the cylinder may be approximately 70 inches, whereas
the stroke may be approximately 260 inches. The overall weight of the
cylinder may be approximately 355 pounds. A skilled reader will recognize
that other embodiments of the present invention may be formed having
varying closed and open volumes, closed lengths, strokes and overall
weights. The embodiment described herein is provided solely to provide
one example of the present invention.

[0037]The present invention may be attachable to a variety of surfaces,
including surfaces of a vehicle. A variety of attachment means may be
employed for the purpose of attaching the present invention to a surface.

[0038]In one embodiment of the present invention, multiple cylinders and a
base may comprise the composite cylinder, such as, for example, such as
six cylinders and a base. Each cylinder may be formed to have a shape
that increases in diameter from top to bottom. Moreover, cylinders may be
formed to be successively sized so that multiple cylinders may fit within
other cylinders. For example, in a collapsed state a composite cylinder
incorporating six cylinders may be positioned so that the a sixth
cylinder fits within a fifth cylinder, the fifth cylinder fits within a
fourth cylinder, the fourth cylinder fits within a third cylinder, and so
on. The cylinders may be extended relative to each other, in a telescopic
manner, whereby the extended length of the composite cylinder will range
from the total length achieved when all of the cylinders are extended, to
the length of the outer cylinder, which is virtually the full length of
the composite cylinder when all of the cylinder are collapsed. In various
levels of extension the composite cylinder may be able to lift an object,
such as, for example a truck trailer, for a specific purpose, such as,
for example unloading.

[0039]In one embodiment of the present invention extension of the
composite cylinder may occur due to hydraulic pressure caused by the
injection of a hydraulic fluid inside the composite cylinder. The
hydraulic fluid may be of several types, including kerosene,
water/antifreeze mixture, or diesel fuel. The application of any
hydraulic fluid that is not the same as the fluid in the fuel tank of the
vehicle may require that an additional hydraulic fluid tank be attached
to the vehicle and the composite cylinder. Utilizing diesel fuel has the
added advantage that such fuel may be obtained directly from the fuel
tank of the vehicle that the composite cylinder is attached to. Utilizing
diesel fuel from the tank of the vehicle negates the need for a separate
tank and consequently reduces the overall weight of the composite
cylinder system.

[0040]In one embodiment of the present invention, hydraulic fluids may be
injected into the cylinder via a threaded port 60. This threaded inlet
port may be located at the saddle lower mount positioned at the lower end
of the composite cylinder. In an embodiment that draws fuel from the
truck fuel tank, a hydrostatic pump may cause fluid to be pumped directly
from the main fuel tank of the truck. The fluid may be pumped directly so
as to cause the lower control for the cylinder to operate to raise the
cylinder. In another embodiment, a fluid tank may be attached to the
truck and hydraulic fluid may be pumped by a hydrostatic pump from the
fluid tank in a manner so as to cause the lower control for the composite
cylinder to operate to raise the cylinders.

[0041]In another embodiment of the present invention, the composite
cylinder may operate by way of double-acting cylinders. Hydraulic fluid
may, be injected into the cylinder by way of a threaded port to cause the
composite cylinder to operate to lower the cylinder. Therefore, the
injection of the hydraulic fluid may exert pressure upon cylinders to
cause them to collapse.

[0042]In yet another embodiment of the present invention, the composite
cylinder may function as a ram or a hoist.

[0043]The flow of hydraulic fluid to and from the cylinders may cause the
cylinders to operate. Pressurized fluid may enter a cylinder via the
inlet port. The fluid may expand within the cylinder and thereby push
against the piston seals. This may cause the cylinders to raise gradually
in stages. As a greater volume of fluid may utilize less pressure per
lifting ton, the largest composite cylinder may be raised first, and the
next largest cylinder may be raised next. This sequence may proceed in
succession, until the last and smallest cylinder is raised. Lowering, or
collapsing, of the cylinders may proceed from the opposite operation.
Therefore, when the composite cylinder is collapsed, the smallest section
of the cylinder may be lowered first.

[0044]The present invention may offer several advantages over the prior
art. For example, the present invention may provide the advantage of
decreased overall weight as compared to the prior art.

[0045]Decreased overall weight may occur for a variety of reasons. First,
a composite cylinder, formed of composite materials, may weigh less, for
example, such as approximately 60% less, than known steel hoists. Second,
should the composite cylinder utilize the fuel of the vehicle the
composite cylinder is positioned upon as the hydraulic fuel, and such
fuel is accessed from the tank of the vehicle, then there will be no need
to include a separate tank for hydraulic fluid, as is required in known
prior art. The hydraulic fluid tank adds weight to the composite cylinder
system that is not required in the present invention. The hydraulic
fluid, tank and brackets may add approximately 500 pounds to the
vehicle's empty weight. Thirdly, by using the vehicle fuel as the
hydraulic fluid, the overall weight of the vehicle load will be decreased
by a reduction of fuel in the tank on the return trip.

[0046]Weight savings may have an effect upon the haulage of the vehicle
and the weight of the return trip. A lower weight while the vehicle is
being driven can produce fuel savings as a lighter vehicle will expend
less fuel. It is estimated that an operator may be able to carry a load
that is approximately 3% greater overall and save on weight by
approximately 1,100 pounds on the empty return trip. The result is that
the haulage may increase for the entire trip and fuel savings may be
experienced on the return trip. Additionally, running the composite
cylinder on the diesel fuel from the vehicle's tank has the result that
there is no reason to change the hydraulic fluid. This has the result of
reduced costs in that the cost of changing the hydraulic fluid is
avoided.

[0047]Another benefit of the present invention is that use of fuel from
the tank of the vehicle as hydraulic fluid may negate the need for
transferring a potentially environmentally hazardous fluid as the
hydraulic fluid in a tank attached to the vehicle. In the case of an
accident, or upon deterioration of the tank, the hydraulic fluid may leak
into the environment. By utilizing the fuel in the tank of the vehicle
the potential environmental hazard caused by leakage is avoided
altogether.

[0048]Yet another benefit of the present invention is that the composite
material used to form the composite cylinder is not subject to either
metal fatigue, rust or pitting. Both fatigue and rust are problems that
affect known prior art hoists. In particular, steel hoists become brittle
and breakage may occur. The cost of repairing breakage, cleaning up rust,
or replacing parts due to fatigue can be high.

[0049]Another benefit of the present invention is that the method of
pultruding the composite cylinders creates a smooth surface that avoids
problems that affect other known prior art. For example, pultruded
composite cylinders eliminate the honing process, fluid leakage and seal
wearing problems. Composite cylinders may be formed from either pultruded
or molded parts. Pultruding and molding the parts can involve fewer
processes and less labour overall to create each composite cylinder unit,
as compared to the creation of known prior art hoists. Additionally the
quality control for each unit may be increased. The result is the
production of composite cylinders that offer improved reliability over
the known prior art hoists.

[0050]Still another benefit of the present invention is that the lower
mount design permits "drop-in" installation on the vehicle. Prior art
applies a side load mount which can cause stress in hydraulic cylinders.
Such stress can further cause seals to wear prematurely. Replacing one
set of seals in a steel hoist can cost a substantial amount, such as, for
example approximately $1000.00 for parts and labour fees. Avoiding
premature seal wearing offers costs savings as well as avoiding
maintenance requirements which may force a cylinder to be unworkable for
a period of time.

[0051]It will be appreciated by those skilled in the art that other
variations of the embodiments described herein may also be practiced
without departing from the scope of the invention. Other modifications
are therefore possible. For example, the composite cylinder may be
utilized to lift a variety of objects that need to be lifted at a
specific point.